STR等位基因频率对父权指数的影响

目的观察中国汉族不同人群STR等位基因频率对联合父权指数(CPI)的影响。方法随机取108例13个CODIS基因座分型结果不排除父权关系的三联体案和二联体案,用5个不同地区人群的等位基因频率计算CPI值。结果三联体案的CPI值在2077.63～50897711626.46之间,同一案例的最大CPI与最小值CPI之比大于100者有20例(19.52%);二联体案的CPI值在25.12～2998685141之间,同一案例的最大CPI与最小值CPI之比大于100者有13例(12.04%)。结论不同人群等位基因频率计算CODIS基因座所得的CPI值在部分亲权鉴定案中有很大的差异。为了防止等位基因频率不确定性带来的误差,建议在亲权鉴定中用保守法计算CPI值。

Diversity of paternity index with different allele frequencies

Objective To evaluate the diversity of combined paternity index (CPI) of multiple STR lociwhen different population allele frequencies was used to calculate the paternity index. Methods CPI of 13CODIS (combined DNA index system) loci for 108 trio cases and 108 duo cases selected randomly werecalculated by using five Chinese Han population allele frequencies, respectively. Results The CPI rangefor trio cases and duo cases were 2077.63- 50897711626.46 and 25.12- 2998685141, respectively. Whendifferent population allele frequencies were applied to the same case, the ratio of maximum CPI and min-imum CPI, which was more than 100, for trio cases and duo cases were 20 cases(19.52%) and 13 cases(12.04%) , respectively. Conclusion The variation of CPI value of the CODIS loci was obvious with dif-ferent allele frequencies. To prevent the error causing by uncertain allele frequencies, a conservative CPIvalue should be calculated in paternity testing.